Electrical relay



ELECTRICAL RELAY Filed sept. 27.1 1928 I f; l @gg /C '22 5"- .="/0 lgg'jgf ...'21

12190 -16 31 16 L24; E 23 Fg gb 27a 5v' 23623 I Mv, ATTORNEY Patented Aug. 18, 1931 'i THOMAS J. OMEARA, OF PITTSBRG-H, PENNSYLVANA, ASSG-NGR T THE UNIONT swr'rorr a sie-Nar.- ooiviiaen, or swissvaan, lA coisrennfrrolv 0F PENNSYLVANIA ELECTRCAL RELAY Application iIed September 27, 1928. Serial No. 308,645.l

My invention relatesA to electrical relays, andparticularly to contact mechanisms for such relays.

I will describe several forms of relay con- I tact mechanisms embodying my invention, and will then pointent the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a view showing, in front elevation, a portion of relay provided with one form of contact mechanism embodying my invention. Fig. 2 is a transverse sectional view along the line II-II of Fig. 1. Fig. 3 is a view showing a portion of the Contact mechanism otFig.

-1 as viewed from the right, Figs. 4 and 5 are views showing modified forms of the contact mechanism illustrated in Fig. 1, and also embodying my invention.

, Similar reference characters refer to similar parts in each ofthe several views.

Referring first to Fig. 1, the reference character 1 designates the top plate of a relay. This top plate 1 is of some suitable insulating material such as Vporcelain or bakelite, and

carries an electromagnet 2. The core 3 of electromagnet 2 passes through the top plate 1, and terminates on the underside of the plate, in a pole piece 4. Securedto the polo piece 4 by means of a screw 35 is a bracket 8 of non-magnetic material. An armature of suitable magnetizable material, such .as soft iron, is pivotallysupported at point 7 by bracket 8, and is arranged to be drawn-upward against a stop 11 in the polerpiece 4 35 when electromagnet 2 is energized.

Attached to the underside of armature 5 by means of insulating'studs 6 is a strip 9 of suitable rigid material such as brass or aluminum. The strip 9 is crimped at 10 to form a notch 40 9al having substantially the shape of an inverted U, and the outer endy of the strip slotted at 34 (see Fig. 3) to lform a bifurcated end. A flexible contact iinger 18, carrying a low resistance contact tip 19, is riveted at '45 its left-hand end to the underside of the strip 9. The right-hand end of t-he inger 18 is bent upward and enters the bifurcated end of the strip 9. The portion of finger 18 above strip 9 has a T-shape, so as to limit the movement ofthe linger away from the strip. This yin its lower position.

construction also permits the finger 18 to be adjusted with an initial tension. When electromagnet 2 is (le-energized, armature 5 drops down under the influence of gravity, andr the tip 19 then engages a back contact 24v fastened to topy plate 1 by a terminal post 25. The finger 13 is provided with a shoulder 36 which is arranged to engage' the unbending of the finger whenthe armature An offset portion 9b of the strip 9 is provided with an upwardly extending adjusting screw 13. The screw 13 is threaded at its lower portion to receive an adjusting nut 14 having a serrated periphery. A knife edge spring 15, heldin place' under the shoulder of the adjusting screwy 13, is arranged to engage the serrations in the nut 14 to lock the ynut in an adjusted position. The screw 13 also carries a coil spring- 17, which is heldin a central position with respect to the screw 13 by means of a saucer shaped washer 16 interposed between the nut 14 and the lower end of the spring. Supportedv on the upper -derside of strip 9 to limit the amountof` A end of the spring 17 is a bar 12 of suitable Y 'rigid material having an oii'set portion 12c to receive thev spring. The bar 12 has both ends bent downwardly to form two lugs 122L and 12b. As best seen in Fig. 2, the lug 12?? is provided with a hole 12e, which receives the strip 9, and which is bounded on the 'lower side by an arc shaped edge 12d. The

arc shaped edge 121 engages a rounded portionV of the bar 9 at the angle of the notch 9a,

thereby forming a pivot about which the bar 12 maybe moved. The lug 12 is provided with a T-shaped end, the neck 12h of which enters the bifurcate'd end of the strip 9 with Aconsiderable clearance, and which neck is vlong enough tojpermit a slight amount of Avertical motion between the bary 12 and the strip 9. (See Fig. 3). It will be noted that the portion of theneck joining thev head of the T is tapered in such manner that the bar 12 will be raccurately centered whenever the head of the T is held against the strip 9.

A contact member 2O is riveted to the bar 12 Lat itsright-hand end, and in the form` heiejsh'own comprises a strap 21 oftlexible material, such as phosphor bronze, having a flexible strip 22 of low resistance conducting material, such as silver gauze, attached to its upwardly bent ends. The member 20 is arranged to co-act with a front contact 30 comprising a block of graphite mounted in a jaw formed in the head of a terminal post 32, which passes up through the top plate l, and which is attached thereto by a nut 33. The parts are proportioned in such manner that when electromagnet 2 is energized, so that armature 5 is drawn upward, the contact member 20 will engage the front contact 30 before the armature has completed its upward stroke. During the remainder of the upward stroke of the armature, therefore, the arc shaped edge 12l of the bar 12 pivots about the strip 9 at the angle of the notch 9, and the spring 17 is compressed. The pressure exerted by the contact member 2O on front contact 30 is therefore dependent upon the amount of compression of the spring 17, and it follows that this pressure may be varied by adjusting the nut 14, thereby previding micrometer adjustment of front contact pressure.

It will be noted that -since the edge 12Cl of the bar 12 is rounded, as shown in Fig. 2, and since considerable clearance is provided between the neck of the f-shaped end of the bar and the bifurcated end of the strip 9 as shown in Fig. 3, then when the contact member 20 is engaging the front contact 30, the bar 12 tends to occupy such a position that the strip 22 conforms to the contour of the face of the front contact 30, thereby giving maximum contact area and providing a low resistance contact. This structure also permits bar 12 to pivot about 12d substantially without frictionwhen the relay closes its front. Contact. Furthermore, since the strip 9 is attached to the armature 5 below the pivot 7, and since the bar 12 is inclined at a slight angle with the strip 9, a slight amount of sliding motion is obtained between the contact member 20 and the front contact 30 whenever the front contact is closed, which sliding motion tends to clean the engaging face of the front contact 3() thereby insuring a good contact.

:In the contact mechanism shown in Fig. et, the offset portion 12C of the bar 12 is provided with a hole 12f, which receives the upper end of an adjusting screw 23 with considerable clearance. The lower end 23a of the adjusting screw 23 is smaller than the remainder of the screw, and extends through the bottom of the offset portion 9b of the bar 9. This end is slotted at 23b and is threaded to receive aI nut 27. A square adjusting nut 31, screwed on the adjusting screw 23, is prevented from turning by engagement with the sides of the offset portion 9b which are perpendicular to the bottom ofthe offset portion throughout the range of movement of the adjusting nut. The saucer shaped washer 16 and the spring 17 are interposed between the nut 2O and the offset portion 12.

lVhen it is desired to change the contact pressure, the nut 27 is loosened, and the screw 23 is turned by inserting a screw driver in the slot 23h. Since the nut 31 is prevented from turning, the nut is moved upward or downward on the screw s3, thereby increasing or decreasing` the pressure exerted by the spring 17 on the bar 12. lVhen the desired pressure has been obtained, the nut 27 is tightened to loclr the parts in the adjusted position.

Referring now to Fig. 5, the bar 12 is constructed without the offset portion 12C, but the bar is provided with two downwardly extending wings 12g only one of which is shown in the drawing. The adjusting screw, here designated 26, has a knurled head 26. Therv 85 shank of the screw adjacent the head extends through a hole 9c in the bottom of the offset portion 9 with considerable clearance, and the upper end 26b of the screw is smaller where it extends through the bai' 12. The; end 26b is threaded to receive a nut 28. An adjusting nut 29 is screwed on the upper part of the screw, and is prevented from turning by the wings 12g. The spring 17 i-s interposed between the nut 29, and the offset' portion 9b, and is centered with respect to the screw 26 by the saucer shaped washer 16, and by a boss 9d formed in the ofi'set portion 9b.

In this modification, adjustment may be made by loosening the nut 2S and turning thev screw 26 with the lingers, thereby moving nut 29 up or down to decrease or increase the pressure exerted by the spring, as desired. When the desired adjustment has been made, the part-s may be locked in position by tightening the nut 28.

Although I have herein shownV and described only a few forms of contact mechanisms embodying my invention, it is understood that various changes and modifications may be made therein within the scope of thev appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1.'In combination, a contact mechanism comprising a rigid strip provided with a notch and having a bifnr ated end, a bar, a first downwardly extending lug integral with said bar at one end of the bar and provided with a hole receiving said strip at said notch in such manner that said bar is pivoted on said strip, a second downwardly extending lug integral with said bar at the other end of the bar and having a T-shaped section the neck of which enters the bifurcated end of said strip with considerable clearance and which is tapered where the head of the T joins the neck to accurately center the bar when the head of said T is in engagement with said strip, a coil springinterposed be- Vtween said bar and said fstrip for exerting a low resistance contact tip attachedto the lower side of said strip.

2. In combination, a contact mechanism comprising a rigid strip provided with a .notch'and having a bifurcated end, a bar, a

first downwardly extending lug integral with said bar at one end of the bar and provided with a hole receiving'said strip in such manner that said baris pivoted on said strip at wsaid notch, a second downwardly extending lug integral with said bar at the other end of the bar and having a T-shaped section the neck of which enters the bifurcated end of said bar with considerable clearance and which is tapered where the head joins tho neck to accurately' center the bar when the head of said T is in engagement with said strip, an offset portion in said bar, an oppositely disposed offset portion in said strip located directly below the offset portion in said bar, an upwardly extending adjusting screw fastened to the offset portion in said strip, `an adjusting nut on said screw having a serrated periphery, a coil spring on said screw interposed between said nut and said offset portion in said bar, a saucer shaped washer interposed between said spring and said nut to center said spring, a knife edge spring arranged to engage the serrations on said nut to lock said nut in an adjusted position, a Contact member riveted to the upper side of said bar, and a contact finger riveted to the lower side of said strip and provided with a low resistance contact tip.

3. In combination, a contact mechanism comprising a rigid strip having a bifurcated T-shaped downwardly extending 'flug the neck of which enters said bifurcated end with considerable clearance, an offset portion in said strip, an adjusting screw extending upwardly from said ofl'setportion, an adjusting nut on said screw having a serrated periphery, a knifeedge spring arranged to engage the serrations in said nut to "lock said nut in an adjusted position, an offset portion in said bar oppositely disposed to the offset portion in said strip and located above the offset portion in said strip, a coilspring on said screw interposed between said nut and the oliset portion of said bar, a saucershaped washer on said screw interposed between said spring and said nut to center said spring,a contact member attached to the upper side of said bar, a front contact, means for at timesy moving said bar upwardly in such manner that said contact member engages saidfront contact to compress said coil spring, a flexible contact finger riveted to the underside of said strip and having one end bent upwardly between the bifurcations of said strip, a low resistance contact tip riveted to said finger at its lower portion, a back contact arranged at times to be engaged by said contact tip, and a shoulder onsaid contact finger arranged to engage said strip to limit the bending of said contact linger when said contact tip engages said back contact.

t. In combination, av contact mechanism coinprising-a moveable strip provided with a notch having substantially the shape of an inverted U, a' bar, a downwardly extending lug integral with said bar at one end of the y: bar and provided with a hole which is bounded on its lower side by an arc shaped edge vand which receives said bar at said notch with considerable clearance to permit said bar to pivot about said arc shaped edge at no the angle of said notch, means located at the other end of the bar for limiting the motion of the bar, an adjusting screw fastened to said strip, an adjusting nut on said screw, a spring onsaid screw between said nut and C said bar and arranged to exert a pressure between said strip and said bar, and a contact member carried by said bar. j

5. In combination, a contact mechanism comprising a movable strip, a bar pivoted at s-00 one end on said strip and provided at the other vend with means for limiting the amount of movement between said bar and said strip, an adjusting screw fastened to said strip, an adjusting nut on said screw, l510|;

means for locking ysaid nut in an adjusted position, a 'spring between saidnut and said bar, and a contact member carried by said `bar.

In combination, a contact mechanism 51:10 comprising a movable strip, a bar pivoted at one j end on said strip and provided at the Y,other end with means forY limiting the amount of movement between said bar and fsaid' strip, an adjusting screw riveted to c1115 said strip, an adjusting nut having a serrated periphery screwed' on said adjusting screw, a knife edge spring clamped between a shoulder of said screw and said strip and arranged to engage the serrations of said tiene nut to lock said nut in an adjusted position,

a` coil spring interposed between said nut and said bar,jand-'a contact member carried by said bar.

7 In combination, a contact mechanism irai comprising a rigid strip having a bifurcated end and provided with a notch having substantially the'shape of an inverted U, a bar pivoted at one end in the notch on said strip and provided at its other end with a down- .13o

said strip and provided with a hole, an adjusting screw having its upper end extending through the hole in the offset portion of said bar and having a lower end of reduced diameter extending through the offset portion in said strip, an adjusting nut screwed on said screw and preventedV from turning by the sides of said offset portion, a coil spring on said screw interposed between said adjusting nut and the offset portion of said bar, a second nut screwed on the lower end of said screw to lock the screw in an adjusted position, a contact member attached to the upper side of said bar, and a contact finger carrying a low resistance contact tip attached to the lower side ot said strip.

8. In combination, a contact mechanism comprising a rigid strip having a biturcated end and provided with a notch having substantially the shape of an inverted U, a bar pivoted at one end in the notch on said strip and provided at its other end with a downwardly extending T-shaped lug the neck of which enters the bifurcated end of said strip in such manner that a limited amount of motion is permitted between said bar and said strip about said pivot, an offset portion in said strip, a boss integral with said offset portion and provided with a hole, an adjusting screw having a lrnurled head and extending upwardly through said hole, an adjusting nut screwed on said adjusting screw, a wing on Y said bar for preventing said nut from turning.` a coil spring interposed between said nut and the Voffset portion of said strip and cene tered at the bottom by said boss, a saucer shaped washer interposed between said nut and the upper end of said spring to center said spring at its upper end, a nut screwed on the upper end of said adjusting screw to lock said screw in an adjusted position,

Aa contact member attached t0 the upper side of said bar, and a contact finger carrying a low resistance contact tip attached to the underside of said strip.

9. In combination, a contact mechanism comprising a movable strip, a bar pivoted at one end on said strip and provided at its other end with means for limiting the amount of movement between said strip and said bar, an offset portion in said bar provided with a hole, an oppositely disposed offset portion i in said strip provided with a hole, an adjusting screw having its upper end extending bar with considerable Vclearance and having a lower kend of reduced diameter extending through the hole in the offset portion of said strip, an adjusting nut screwed on said adjusting screw and prevented from turning by? the sides of said offset portion of t-he strip, a spring on said screw interposed between said nut and said bar, a Contact member carried by said bar, and a second nut screwed on the lower end of said adjusting screw toc5 lock the screw in an adjusted position.

l0. In combination, a contact mechanism comprising a movable strip, a bar pivoted at one end on said strip and provided at its other end with means i'or limiting the amount of movement between said bar and said strip, an offset portion in said strip provided witli a hole, an adjusting screw extending upwardly through the hole in said offset portion and having an upper end of reduced diameterc35 extending through said bar, an adjusting nut on saidscrew, a wing on said bar for preventing said adjusting nut from turning, a. coil spring on said adjusting screw interposed between said nut and the offset portion of E ture.

THOMAS J. OMEARA.

through the hole in the offset portion of said 

